Add testcase for column pruning enable case

Author: sandeep-katta

sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/csv/UnivocityParser.scala

@@ -188,13 +188,13 @@ class UnivocityParser(
     }
   }
 
-  // parse if the columnPruning is disabled or requiredSchema is nonEmpty
-  private val doParse = if (!options.columnPruning || requiredSchema.nonEmpty) {
-    (input: String) => convert(tokenizer.parseLine(input))
-  } else {
+  private val doParse = if (options.columnPruning && requiredSchema.isEmpty) {
     // If `columnPruning` enabled and partition attributes scanned only,
     // `schema` gets empty.
     (_: String) => InternalRow.empty
+  } else {
+    // parse if the columnPruning is disabled or requiredSchema is nonEmpty
+    (input: String) => convert(tokenizer.parseLine(input))
   }
 
   /**